package com.firesrc.util;

import java.text.DecimalFormat;
import java.text.FieldPosition;
import java.text.Format;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;

public class GenerateSequenceUtil {

	/** .log */

	/** The FieldPosition. */
	private static final FieldPosition HELPER_POSITION = new FieldPosition(0);

	/** This Format for format the data to special format. */
	private final static Format dateFormat = new SimpleDateFormat("yyyyMMddHHmmssS");

	/** This Format for format the number to special format. */
	private final static NumberFormat numberFormat = new DecimalFormat("0000");

	/** This int is the sequence number ,the default value is 0. */
	private static int seq = 0;

	private static final int MAX = 9999;

	/**
	 * 时间格式生成序列
	 * @return String
	 */
	public static synchronized String generateSequenceNo() {

		Calendar rightNow = Calendar.getInstance();

		StringBuffer sb = new StringBuffer();

		dateFormat.format(rightNow.getTime(), sb, HELPER_POSITION);

		numberFormat.format(seq, sb, HELPER_POSITION);

		if (seq == MAX) {
			seq = 0;
		} else {
			seq++;
		}

		return sb.toString();
	}
}